fixed 返回顶部功能

themes/Ying/static/js/main.js

@@ -10,12 +10,43 @@ function isMobile() {
 // 文章图片灯箱
 window.ViewImage && ViewImage.init('.post-content img');
 
-// 激活返回顶部插件 
-$(function () {
-  $.scrollUp({
-    animation: 'fade',
-    scrollImg: true
-  });
+// Pure JavaScript Back to Top (High Performance)
+document.addEventListener('DOMContentLoaded', function() {
+    var backToTopButton = document.getElementById('back-to-top');
+    if (backToTopButton) {
+        var isVisible = false;
+        var ticking = false;
+
+        function update() {
+            if (window.scrollY > 300) {
+                if (!isVisible) {
+                    backToTopButton.classList.add('show');
+                    isVisible = true;
+                }
+            } else {
+                if (isVisible) {
+                    backToTopButton.classList.remove('show');
+                    isVisible = false;
+                }
+            }
+            ticking = false;
+        }
+
+        window.addEventListener('scroll', function() {
+            if (!ticking) {
+                window.requestAnimationFrame(update);
+                ticking = true;
+            }
+        }, { passive: true });
+
+        backToTopButton.addEventListener('click', function(e) {
+            e.preventDefault();
+            window.scrollTo({
+                top: 0,
+                behavior: 'smooth'
+            });
+        });
+    }
 });
 
 // loader定时器